Hi,
I have an '88 Pathfinder that has been on life-support for the last year or so. Still, it's my daily driver and I'd like to keep driving it.
Anyway, I recently fixed most of the engine problems, but still have troube on acceleration. The engine stumbles at 2750 RPM and won't go any faster.
Reading online, I suspect it is in failsafe mode. Can someone here direct me to info I can read to understand what this is, how it works and how to fix it?

Fail safe mode is designed to protect the engine/trans from farther damage or to protect the driver due to an unsafe condtion that may exsist.Go to the EC section of the nissan service manual and you can read more about this mode.

yes, MAF is the reason to this. when there is no signal or signal is beyond programmed limits, car is in fail safe mode. check for MAF sensor connectors for broken wires, then remove it and spray brake pad cleaner, and try once more. you will need to reset ecu.